The research generally involves use of nmr to measure the structure and dynamics of tRNA in solution. Much of an effort is directed toward resonances of modified bases found in all tRNA's. tRNA 1 Val and tRNA Phe from E. Coli are the major species used. We have discovered that certain aromatic carbon-bound protons give resolved, narrow peaks for tRNA in its native structure. The resonances arise from H-2 of A and H-8 of certain purines involved in non-regular structure, and will be used to probe structure in helical and loop regions of tRNA.